std::function::function

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

optional, any and variant (C++17)

optional

any

variant

in_placein_place_typein_place_indexin_place_tin_place_type_tin_place_index_t

Pairs and tuples

pair

tuple (C++11)

apply (C++17)

make_from_tuple (C++17)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

integer_sequence (C++14)

Swap, forward and move

swap

exchange (C++14)

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

Elementary string conversions

to_chars (C++17)

from_chars (C++17)

chars_format (C++17)

Type operations

declval (C++11)

as_const (C++17)

 

Function objects

Function wrappers function (C++11) mem_fn (C++11) bad_function_call (C++11) invoke (C++17)	Bind bind (C++11) is_bind_expression (C++11) is_placeholder (C++11) _1, _2, _3, ... (C++11)
Reference wrappers
reference_wrapper (C++11)
refcref (C++11)(C++11)
Operator wrappers
plus minus negate multiplies divides modulus logical_and logical_or logical_not	equal_to not_equal_to greater less greater_equal less_equal bit_and bit_or bit_xor bit_not (C++14)
Negators
not_fn not1 (deprecated) not2 (deprecated)	unary_negate (deprecated) binary_negate (deprecated)
Searchers
default_searcher (C++17)
boyer_moore_searcher (C++17)
boyer_moore_horspool_searcher (C++17)
Old binders and adaptors
unary_function (until C++17) binary_function (until C++17) ptr_fun (until C++17) pointer_to_unary_function (until C++17) pointer_to_binary_function (until C++17) mem_fun (until C++17) mem_fun_tmem_fun1_tconst_mem_fun_tconst_mem_fun1_t (until C++17)(until C++17)(until C++17)(until C++17)	binder1stbinder2nd (until C++17)(until C++17) bind1stbind2nd (until C++17)(until C++17) mem_fun_ref (until C++17) mem_fun_ref_tmem_fun1_ref_tconst_mem_fun_ref_tconst_mem_fun1_ref_t (until C++17)(until C++17)(until C++17)(until C++17)

 

std::function

Member functions

function::function

function::~function

function::operator=

function::swap

function::assign (until C++17)

function::operator bool

function::operator()

function::target_type

function::target

Non-member functions

operator==operator!=

std::swap(std::function)

Helper classes

std::uses_allocator<std::function> (until C++17)

 

function();	(1)	(since C++11)
function( std::nullptr_t );	(2)	(since C++11)
function( const function& other );	(3)	(since C++11)
function( function&& other );	(4)	(since C++11)
template< class F > function( F f );	(5)	(since C++11)
template< class Alloc > function( std::allocator_arg_t, const Alloc& alloc );	(6)	(since C++11) (until C++17)
template< class Alloc > function( std::allocator_arg_t, const Alloc& alloc,           std::nullptr_t );	(7)	(since C++11) (until C++17)
template< class Alloc > function( std::allocator_arg_t, const Alloc& alloc,           const function& other );	(8)	(since C++11) (until C++17)
template< class Alloc > function( std::allocator_arg_t, const Alloc& alloc,           function&& other );	(9)	(since C++11) (until C++17)
template< class F, class Alloc > function( std::allocator_arg_t, const Alloc& alloc, F f );	(10)	(since C++11) (until C++17)

Constructs a std::function from a variety of sources.

1-2) Creates an empty function.

3-4) Copies (3) or moves (4) the target of other to the target of *this. If other is empty, *this will be empty after the call too. For (4), other is in a valid but unspecified state after the call.

5) Initializes the target with a copy of f. If f is a null pointer to function or null pointer to member, *this will be empty after the call. This constructor does not participate in overload resolution unless f is Callable for argument types Args... and return type R. (since C++14)

6-10) Same as (1-5) except that alloc is used to allocate memory for any internal data structures that the function might use.

When the target is a function pointer or a std::reference_wrapper, small object optimization is guaranteed, that is, these targets are always directly stored inside the std::function object, no dynamic allocation takes place. Other large objects may be constructed in dynamic allocated storage and accessed by the std::function object through a pointer.

Parameters

other	-	the function object used to initialize *this
f	-	a callable used to initialize *this
alloc	-	an Allocator used for internal memory allocation
Type requirements
- F must meet the requirements of Callable and CopyConstructible.
- Alloc must meet the requirements of Allocator.

Exceptions

1-2)

noexcept specification:  

noexcept

  

3,4,8,9) does not throw if other's target is a function pointer or a std::reference_wrapper, otherwise may throw std::bad_alloc or any exception thrown by the constructor used to copy or move the stored callable object.

5,10) does not throw if f is a function pointer or a std::reference_wrapper, otherwise may throw std::bad_alloc or any exception thrown by the copy constructor of the stored callable object.

6-7)

noexcept specification:  

noexcept